The Mets have claimed submarine lefty Jay Marshall off waivers from Oakland. Marshall is 26-years-old and has been quite good against lefties in the equivalent of 99.1 minor league innings. He's an extreme groundball pitcher, with a career minor league GB:FB ratio of almost 3. His stuff is unspectacular, but he's interesting enough to make this a worthwhile pickup.
You can check out his career numbers at Minor League Splits.